5.1 Protection of a species requires prevention of unacceptable effects on the number, weight, health, and uses of the individuals of that species. An early life-stage toxicity test provides information about the chronic toxicity of a test material to a species of fish. The primary adverse effects studied are reduced survival and growth.

5.2 Results of early life-stage toxicity tests are generally useful estimates of the results of comparable life-cycle tests with the same species (1).4 However, results of early life-stage tests are sometimes under estimative of those obtained with the same species in the longer life-cycle tests (2).

5.3 Results of early life-stage toxicity tests might be used to predict long-term effects likely to occur on fish in field situations as a result of an exposure under comparable conditions, except that motile organisms might avoid exposure when possible.

5.4 Results of early life-stage toxicity tests might be used to compare the chronic sensitivities of different fish species and the chronic toxicities of different materials, and to study the effects of various environmental factors on results of such tests.

5.5 Results of early life-stage toxicity tests might be an important consideration when assessing the hazards of materials to aquatic organisms (see Guide E1023) or when deriving water quality criteria for aquatic organisms (3).

5.6 Results of an early life-stage test might be useful for predicting the results of chronic tests on the same test material with the same species in another water or with another species in the same or a different water. Most such predictions take into account the results of acute toxicity tests, and so the usefulness of the results of an early life-stage test is greatly increased by reporting also the results of an acute toxicity test (see Guide E729) conducted with juveniles of the same species under the same conditions.

5.8 Results of early life-stage toxicity tests will depend on temperature, composition of the dilution water, condition of the test organisms, and other factors.

1. Scope

1.1 This guide describes procedures for obtaining laboratory data concerning the adverse effects of a test material added to dilution water—but not to food—on certain species of freshwater and saltwater fishes during 28 to 120-day (depending on species) continuous exposure, beginning before hatch and ending after hatch, using the flow-through technique. This guide will probably be useful for conducting early life-stage toxicity tests with some other species of fish, although modifications might be necessary.

1.2 Other modifications of these procedures might be justified by special needs or circumstances. Although using appropriate procedures is more important than following prescribed procedures, results of tests conducted using unusual procedures are not likely to be comparable to results of many other tests. Comparison of results obtained using modified and unmodified versions of these procedures might provide useful information concerning new concepts and procedures for conducting early life-stage toxicity tests with fishes.

1.3 These procedures are applicable to all chemicals, either individually or in formulations, commercial products, or known mixtures, that can be measured accurately at the necessary concentrations in water. With appropriate modifications these procedures can be used to conduct tests on temperature, dissolved oxygen, and pH and on such materials as aqueous effluents (see Guide E1192), leachates, oils, particulate matter, sediments, and surface waters.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 6 and 9.